A float glass is manufactured by using a typical float process. That is, by introducing the molten glass to an upper portion of molten tin that has the large specific gravity and is included in the molten tin bath to use a float process that manufactures a panel glass having no unevenness, it is manufactured.
However, when the panel glass is manufactured by using the molten tin bath, there is a large technical problem in a known manufacturing process in that there is a bottom open seed due to oxides of tin or oxygen dissolved in tin.
Therefore, in order to solve this, a technology in which an atmosphere of the molten tin bath is maintained under an atmosphere having no oxygen, and sealing is carried out so as to prevent inflow of air and consequently to prevent oxygen from being dissolved in tin has been developed. However, since this is not suitable to sufficiently remove oxygen that is dissolved in tin, there is a difficulty in reduction of product defect ratios.